Learn a Linux command every day (24): chattr / Lsattr

Brother of migrant workers 2021-01-21 19:56:33
learn linux command day chattr


chattr Used to change files ( Expand ) attribute . Usually we call this property a special property .

lsattr View file extension properties .

This special property has the following 8 Patterns :

a # The qualification file has some function . This is very useful for log files , such as , Deletion is not allowed , Only content can be added to it .
b # Do not update or modify the last storage time of a file or directory
c # Compress a file or directory and store it
d # Exclude files or directories from the dump operation
i # Lock file or directory , Not changed
s # Secretly delete files or directories
S # Dynamically update files or directories in real time
u # Prevent files or directories from being accidentally deleted 

If the file or directory is configured with the above 8 One of the extended properties , adopt lsattr The command can see :

[root@centos7 testdir]# lsattr
----i----------- ./dir
# The result shows that the directory is configured with extended properties
[root@centos7 testdir]# chattr -i dir
[root@centos7 testdir]# lsattr
---------------- ./dir

Grammar format

chattr [ Options ] mode file
lsattr [ Options ] file

Option description

chattr Option description

-R # Recursive processing , Add this extended attribute to all files and subdirectories in the directory
-v< Version number > # Set the file or directory version number
-V # Display during execution of instructions ;
+ < attribute > # Add an extended property of a file or directory
- < attribute > # Release an extended attribute of a file or directory
= < attribute > # Specify an extensibility to a specified file or directory 

lsattr Option description

-E # Displays the current value of the property
-D # Displays the name of the extended property
-R # recursive
-V # Display version information
-a # List all files in the directory , Including hidden files
# Be careful -E -D -R The three options can't be used together , They are mutually exclusive .

Application, for example,

# The function of preventing false deletion
[root@centos7 testdir]# chattr +a test2.txt
[root@centos7 testdir]# lsattr test2.txt
-----a---------- test2.txt
# Direct substitution is not allowed , Only additional content is allowed
[root@centos7 testdir]# echo "12345">test2.txt
-bash: test2.txt: Operation not permitted
# See if the file or directory has extended properties
[root@centos7 testdir]# echo "12345">>test2.txt
[root@centos7 testdir]# lsattr
---------------- ./dir
---------------- ./test2.txt~
-----a---------- ./test2.txt
lsattr: Operation not supported While reading flags on ./cp

These two commands are also commonly used in daily work , Lock file , Or when a file or system fails, it can be used for troubleshooting .

[root@centos7 testdir]# lsattr
---------------- ./dir
---------------- ./test2.txt~
----i----------- ./test2.txt
lsattr: Operation not supported While reading flags on ./cp
[root@centos7 testdir]# echo "12345">>test2.txt
-bash: test2.txt: Permission denied

For example, the above situation , If this file is a file to store data in real time , locked , Then it may cause application running failure , therefore , Now you can go through lsattr Command to view and check .

This article is from WeChat official account. - The road of technology for migrant workers (jishuroad)

The source and reprint of the original text are detailed in the text , If there is any infringement , Please contact the yunjia_community@tencent.com Delete .

Original publication time : 2021-01-21

Participation of this paper Tencent cloud media sharing plan , You are welcome to join us , share .

版权声明
本文为[Brother of migrant workers]所创,转载请带上原文链接,感谢
https://javamana.com/2021/01/20210121195549418N.html

  1. 【计算机网络 12(1),尚学堂马士兵Java视频教程
  2. 【程序猿历程,史上最全的Java面试题集锦在这里
  3. 【程序猿历程(1),Javaweb视频教程百度云
  4. Notes on MySQL 45 lectures (1-7)
  5. [computer network 12 (1), Shang Xuetang Ma soldier java video tutorial
  6. The most complete collection of Java interview questions in history is here
  7. [process of program ape (1), JavaWeb video tutorial, baidu cloud
  8. Notes on MySQL 45 lectures (1-7)
  9. 精进 Spring Boot 03:Spring Boot 的配置文件和配置管理,以及用三种方式读取配置文件
  10. Refined spring boot 03: spring boot configuration files and configuration management, and reading configuration files in three ways
  11. 精进 Spring Boot 03:Spring Boot 的配置文件和配置管理,以及用三种方式读取配置文件
  12. Refined spring boot 03: spring boot configuration files and configuration management, and reading configuration files in three ways
  13. 【递归,Java传智播客笔记
  14. [recursion, Java intelligence podcast notes
  15. [adhere to painting for 386 days] the beginning of spring of 24 solar terms
  16. K8S系列第八篇(Service、EndPoints以及高可用kubeadm部署)
  17. K8s Series Part 8 (service, endpoints and high availability kubeadm deployment)
  18. 【重识 HTML (3),350道Java面试真题分享
  19. 【重识 HTML (2),Java并发编程必会的多线程你竟然还不会
  20. 【重识 HTML (1),二本Java小菜鸟4面字节跳动被秒成渣渣
  21. [re recognize HTML (3) and share 350 real Java interview questions
  22. [re recognize HTML (2). Multithreading is a must for Java Concurrent Programming. How dare you not
  23. [re recognize HTML (1), two Java rookies' 4-sided bytes beat and become slag in seconds
  24. 造轮子系列之RPC 1:如何从零开始开发RPC框架
  25. RPC 1: how to develop RPC framework from scratch
  26. 造轮子系列之RPC 1:如何从零开始开发RPC框架
  27. RPC 1: how to develop RPC framework from scratch
  28. 一次性捋清楚吧,对乱糟糟的,Spring事务扩展机制
  29. 一文彻底弄懂如何选择抽象类还是接口,连续四年百度Java岗必问面试题
  30. Redis常用命令
  31. 一双拖鞋引发的血案,狂神说Java系列笔记
  32. 一、mysql基础安装
  33. 一位程序员的独白:尽管我一生坎坷,Java框架面试基础
  34. Clear it all at once. For the messy, spring transaction extension mechanism
  35. A thorough understanding of how to choose abstract classes or interfaces, baidu Java post must ask interview questions for four consecutive years
  36. Redis common commands
  37. A pair of slippers triggered the murder, crazy God said java series notes
  38. 1、 MySQL basic installation
  39. Monologue of a programmer: despite my ups and downs in my life, Java framework is the foundation of interview
  40. 【大厂面试】三面三问Spring循环依赖,请一定要把这篇看完(建议收藏)
  41. 一线互联网企业中,springboot入门项目
  42. 一篇文带你入门SSM框架Spring开发,帮你快速拿Offer
  43. 【面试资料】Java全集、微服务、大数据、数据结构与算法、机器学习知识最全总结,283页pdf
  44. 【leetcode刷题】24.数组中重复的数字——Java版
  45. 【leetcode刷题】23.对称二叉树——Java版
  46. 【leetcode刷题】22.二叉树的中序遍历——Java版
  47. 【leetcode刷题】21.三数之和——Java版
  48. 【leetcode刷题】20.最长回文子串——Java版
  49. 【leetcode刷题】19.回文链表——Java版
  50. 【leetcode刷题】18.反转链表——Java版
  51. 【leetcode刷题】17.相交链表——Java&python版
  52. 【leetcode刷题】16.环形链表——Java版
  53. 【leetcode刷题】15.汉明距离——Java版
  54. 【leetcode刷题】14.找到所有数组中消失的数字——Java版
  55. 【leetcode刷题】13.比特位计数——Java版
  56. oracle控制用户权限命令
  57. 三年Java开发,继阿里,鲁班二期Java架构师
  58. Oracle必须要启动的服务
  59. 万字长文!深入剖析HashMap,Java基础笔试题大全带答案
  60. 一问Kafka就心慌?我却凭着这份,图灵学院vip课程百度云